The focus of that event is Windows 10, and many believe how it will work on Windows Phone devices will also be detailed.

Now, a new version of the app – with a different name – has been found in the Store. Dubbed Windows Previewer Beta , the app appears to be an internal test version of the app. Windows Phone app developer and XDA forum moderator Jeremy Sinclair has also managed to pull out a few screenshots and details from the app.

It should be noted that this app cannot be downloaded by the public like Phone Insider as the app is marked private.

According to the app's description:

"The update provisioning application allows users to get early access to the latest Windows Phone updates for the purposes of providing feedback to Microsoft on current releases. Feedback is gathered automatically from the device by configuring your device for early access. For more information see the terms and conditions below."

Sinclair broke down the app and learned a few new things about this version, which he has kindly shared with Windows Central. Additionally, he provided exclusive screenshots taken from the app itself and seen above.

"Basically, this app enables a few new Authentication methods. First it tries to auth with the built-in Microsoft Account on your device. If it fails for any reason such as not having access to any Windows Phone flights for the Insider program, it leads you to the AlternateLogon page. This page allows for you to manually login with a Microsoft Account or to login with an internal Microsoft account."

"Still not useful for us who haven't been deployed access to all the joy, but this shows as confirmation that the next update to the Phone Insider app will involve a rename and allow for us to login to it once it goes live."

It should be interesting to see if the app (and program) remains Phone Insider or if it will be called Windows Previewer upon its public release. Regardless, all of this heavily suggests that Microsoft is on the cusp of releasing Windows 10 for Phone very soon to the public, albeit in early preview form via the Windows Insider Program.

You can see the Windows Previewer Beta app here on the Store, but note that you cannot download it due to it being a private app.